Transparent sheet



handle.

Patented Mar. 4, 1930 UN 'r-EDsTATEs PATENT OFFICE.

mime GEN'rILE, or cnrcaeo, rumors, ASSIGNOR or ONE-HALF 'ro SAMU L w. wars, A m onn roun'rn' 'IQ eaoaea PICK, BOTH or cnrcaeo, ILLINOIS mnsraann'r seam Ho Drawing. I

this material such' filmsbreak or tear easily and soon soften and disintegrate, especially m in damp climates; Films made of cellulose nitrate, or gun cotton, have also been known, but owing tothe high combustibility ofthis material, it is more The object of my present invention is to provide 'a' thin, fle xible, and durable tissue which shall be non-porous and impervious .to dust and moisture, of low combustibility, highly transparent, cheap to manufacture,

- and amply strong to serve the purpose of a.

v wrapper, seal, or container for food and other products under all climatic and atmospheric conditions. I

In carrying out my invention, I start with a thin filmor sheetof a protein substance such as elatin, casein or albumen, all 0 which su%stances are capable of being prepared in the form of a thin transparent film,

and I then coat this film, preferably on both sides, with a solution containing cellulose nitrate as its chief ingredientf -This coating solution? may be prepared by 'first' dissolving .the cellulose nitrate in a suitable solvent such as ethyl acetate, amyl acetate, ether, etc.,

which yields a thick or viscous product, and

then- .thinning-the tter to .a freely flowing state by the additio of a suitable-amount of alcohol. To this cellulose nitrate solution is then added a non-hygroscopic material which 40 renders the same soft and pliable, vwhen dry,

- andalso causes it to adhere evenly and uniforml to the gelatin or other protein film; the 'su stance whichI have found best adapted to this purpose beingcastor oil. For practical purposes proportions of 40% to 60% of -ping films or sheets ofgelatin have heretofore or less dangerous to limit the invention, in its broadest aspect, to

Application flled February 11, 1928. Serial masawaz.

castor oil, by wei ht, of the dried coating of a cellulose nitrate lxas proven to be satisfactory. n

The coating solution can be applied to the base film or sheet in any suitable way, as by di ping the base sheet in, or drawing it th ough, a body of the coating solution, or by flowing the latter over, or brushing it on, the base sheet. When the coating or covering has dried, the resultant product is a tough flexible, transparent sheet of greater strength" for the same thickness than either gelatin or gun cotton alone, less combustible than ordinary paper, non-porousand impervious to dust, grease and moisture and thus excellently adapted to serve the purpose of a sanitary wrapper "or container, especially for food products, medicines, and the like, and low in ,cost of materials and manufacture. And while I have found that the materials-best adapted to. serve all the purposes and characteristics of the invention are gelatinfor the base film, and cellulose nitrate admixed with castor oil for the coating or covering, I do not 0 all of these substances, but may employ such equivalents as are adapted to yield a product having the qualities'and characteristics hereinabove. described. I

I'claim- I 1. An integral transparent'wrapping sheet of the character described consisting of a thin filmof gelatin as a base, a'coating of cellulose nitrate having castor oil incorporated therein applied to each faceof said gelatin film, the castor oil functioning as anon-hygroscopic bonding agent and causing the cellulose nitrate coatin to become integrally united with the gelatin m on each" side thereof, said re sultant wrapping sheet being tough, pliable transparent, moisture, grease and water proof and being adapted to readilyconform to the "shape of packages and the like without cracking or separating.

of the character described consisting of a thin protein film as a base, a coating of cellulose nitrate having castor oil incorporated therein applied to each face of said protein film,'the castor oil functioning as a non-hygroscopic bonding agent and causing the cel- .lulose nitrate coating to become integrally united with the protein film on each side thereof, said resultant wrapping sheet being tough pliable, transparent, m0isture, grease and Water proof and being adapted to readil conform to the shape of packages and the lie Without cracking or separating.

' MARINO GENTILE. 

